Electric switch.



No. 764,189. 7 C PATENTED JULY 5, 1904. J. F. HARDY. ELECTRIC SWITCH.

APPLICATION FILED MAR. 4, 1903.

H0 MODEL. 3 SHEETS-SHEET l.

ZI Z IZtSQS: F [W12]??? J. M v M M m M 4 W No. 764,189. PATENTED JULY 5,1904. J. F. HARDY. ELECTRIC SWITCH.

APPLICATION FILED MAR. 4, 1903. no MODEL. a SHEETS-SHEET 2.

No. 764,189. PATENTED JULY 5, 1904. J. F. HARDY.

ELECTRIC SWITCH.

APPLIOATION FILED MAB. 4. 1903. N0 MODEL.

3SHEBTS-SHEET 3- UNITED STATES Patented July 5, 1904.

PATENT tr es.

JAMES F. HARDY, OF NEl/V YORK, N. Y., ASSIGNOR TO CONSOL1DA"ED DENTALMANUFACTURING OOMPANY, OF NEW YORK, N. Y, A COR- PORATION OF NEI/V YORK.

ELECTRIC SWITCH.

SPECIFICATION forming part of Letters Patent No. 764,189, dated J lily5, 1904.

Application filed March I, 1903. Serial No. 146,066. (No model.)

To all whmn it may concern:

Be it known that I, JAMES F. HARDY, acitizen of the United States, and aresident of the borough of Manhattan, in the city and State of New York,have invented a new and useful Improvement in Electric Switches, ofwhich the following is a specification.

My invention relates to an improvement in electric switches, and has forits object to provide a switch for controlling the movements of anelectric-motor shaft which is so constructed that it will be operated bya part moved by the shaft when the part reaches a predetermined pointfor automatically stopping the motor-shaft.

A further object is to provide an electric switch comprisinga suitablesupport, a switchboard pivoted, to swing on the support, and aswitch-lever also pivoted to swing on the said support.

A practical embodiment of my invention is represented in theaccompanying drawings, in which I have represented the switch inconnection with means for raising and lowering 5 the seat-support of achairsuch, for instance,

as a surgical or dental chair.

Figure 1 represents in top plan the base and seat-support of a chair,showing the position of my improved switch on the base.

3 Fig. 2 is a view in side elevation of the same. Fig. 3 is a verticalcentral section. Fig. i is a partial horizontal section taken in theplane of the lineAA of Fig. 3. Fig. 5 is an enlarged detail view, inside elevation, of the means for automatically operating the switch whenthe seat-support reaches the limit of its upward or downward movement.Fig. 6 is a front view showing a fragment of the switch. Fig. 7 is apartial transverse section taken in 4 the plane of the line B B of Fig.6. Fig. 8 is a view in side elevation of the switch in its normalposition, a portion of its support being also shown. section through thesame. Fig. 10 is a rear view. Fig. 11 is a top plan View of the rockingswitchboard with the contact-plates in position thereon, and Fig. l2isan inverted plan view of the same.

The lower or stationary section of thebase Fig. 9 is a vertical centralof the chair is denoted by l, and the upper 5 section, which is mountedto rotate upon the lower section,is denoted by 2. Theverticallyreciprocating seat-support is herein represented as composedof the following parts:

A tubular-post 3, which is fitted to have the chair-seat (not shownherein) secured thereto,

is fitted to slide vertically in a secondary tubular post I, which postis in turn fitted to slide in the upper or rotary section 2 of the base.A stationary exteriorly-cut screw 5 is permanently secured at its upperend in the upper end of the inner tubular post 3 and projects downwardlytherein to a point near the bottom of the said post. A hollowexteriorly-threaded rotary screw 6 surrounds 5 the stationary screw 5and has fixed thereto at its upper end an interiorly-screw-threaded nut7 which fits the threads of the screw 5,

so that when the screw 6 is rotated the screw 5, and thereby the hollowpost 3, is moved up 7 or down, according to the direction in which thescrew 6 is rotated. An interiorly-screwthreaded traveling nut 8 issecured to the lower end of the tubular post 4 and engages the threadsupon the screw 6, so that when the screw 6 is rotated the hollow post 4:will be moved up or down, according to the direction in which the screwis rotated.

The screws 5 and 6 are threaded in the same direction, but havedifferent pitches for sending the two posts 3 and a up or down atdifferent speeds.

A bevel-gear 9 is keyed to the lower end of the rotary screw 6, whichbevel-gear intermeshes with a driving bevel-gear 10, loosely 5 mountedupon a stud-axle 11, secured to the rotary section 2 of the base.

The means which I have shown for positively moving the seatsupport up ordown, as may be required, is as follows: An electric 9 motor 12 of anysuitable type is supported upon the movable section 2 of the base, so asto be free to be turned therewith into any position which it may berequired to have the person in the chair occupy. The motor-shaft 13projects into the interior of the rotarysection 2 of the base across thespace above the stud-axle 11, which shaft 13 preferably has its outerend mounted in suitable bearing 14 on the interior wall of the saidrotary section 2. This motor-shaft 13has a worm-and-gear connection withthe bevel-gear 10 on the studaXle as follows: A worm 15 is carried bythe shaft 13, and a gear 16 is fixed to the bevelgear 10, but looselymounted on the stud-axle 11. The relation between the worm and gear maybe such as to produce the best results in operating the motor andseat-support.

The switch which I employ for starting the motor-shaft to rotate in oneor theother direction or to stop the same is constructed, arranged, andoperated as follows: The wall of the rotary section 2 of the base is cutaway, as shown at 17, at any suitable place in the said section for theinsertion and removal of the switch. This cut-away portion is closed bymeans of a switch-supporting plate 18,

- of the board. Upon one side of these three contact-plates are locatedtwo dead-plates 27 28. Upon the other side of these three plates arelocated two dead-plates 29 30. Beyond the dead-plates 29 and 30 arelocated contact-plates 31 32, and beyond the dead-plates 27 28 arelocated two contact-plates 33 34. The plates 27 and 33 are located atthe same distance from the pivot of the switchboard as the contact-plate24. The plates 34, 28, 29, and 31 are located at the same distance fromthe pivot of the switchboard as the plate 25. The plates 30 32 arelocated at the same distance from the pivot as the plate 26.

The wires which connect the motor with the switchboard are denoted by35, 36, 37, and 38. The wire 38 leads to the contact-plate 34 and fromthence by a branch 39 to the contactplate 31. The wire 37 leads to thecontactplate 33 and from thence by a branch 40 to the contact-plate 24.The wire 36 leads to the contact-plate 25. The wire 35 leads to thecontact-plate 32 and from thence by a branch wire 41 to thecontact-plate 26.

Two sets of brushes 42 43 project from opposite sides of the arm 44 ofthe switch-lever, which switch-lever is provided with a suitable hub 45,fitted to embrace the pivot-pin ,20, upon which the switchboard 21 issupported.

The switch-lever is provided with an outwardly projected arm 46, whichprojects through the plate 18 to the exterior of the base, whereby theswitch may be moved bythe foot of the operator to swing the brushes intoposition to drive the motor in one direction or the other, as may bedesired.

The brushes 42 are so arranged that they will travel over the pairs ofcontact-plates 33 34, 27 28, and 24 25. ted to travel over thecontact-plates 31 31, 29 30, and 25 26.

The switch-lever is held normally in its intermediate position by meansof a double-acting spring 47 as follows: This spring47 is coiled aroundthe upper end of the pin 20 above the switchboard and lever, and theends of the spring are engaged with arms 48 49, pivoted on the pivot-pin20.

The tendency of the spring is to swing these arms toward each other, andthey are held at 'the limit of this movement by means of a stop 50,projecting upwardly from "the switchboard, and a stop 51, projectingupwardly from the switch-lever. Y

The switchboard is normally held against movement on its pivot-pin 20 bymeans of curved rack 52, which engages a pinion 53,

which pinion is only rotated at predetermined times, as will behereinafter fully set forth.

As the switch-lever is swung in onedirection the stop 51 will engage oneof the armstion it will cause the motor to raise the seatsupport, andwhen the switch-lever is swung in the opposite direction it will firststop the The brushes 43 are fit-- motor and then reverse it to cause themotor 1 to drive the seat-support in the opposite direction.

To prevent accidents owing to the switch' lever being held too long inposition to operate the motor in one direction, I provide means forautomaticaly shifting the switch board to stop the motor when theseatsup port reaches the limit of its upward or downward movement, whichmeans is constructed,-

arranged, and operated as follows: A vertically-sliding spring-actuatedplate 54 is yieldingly held intermediate the limits of its movements bymeans of a coil-spring 55, located in the plate-support 56, the ends ofwhich springs press against upper and lower inwardly-turned cars 57 58of the plate, which ears are fitted to slide in vertical grooves 59 60,opening into the socket 61, in which the spring 55 is located. The plate54 is held on its support by means of pin-and-slot connections 62 63.

The support 56 is secured to the interior of the rotary section 2 of thebase, preferably by providing the support with a flange 64' and thesection 2 with a flange 65, upon which the flange 64 rests.

The plate 54; is provided with upper and lower lips 66 67, which arearranged to be successively engaged by an abutment 68 on the tubularpost 4: as the seat-support nears the limit of its upward and downwardmovements. support in these directions will impart a slight slidingmovement to the plate 54.

The plate 54 is provided with a rack 69, which engages a pinion 70,fixed to a horizontal shaft 71, mounted in suitable hearings in abracket 72, projecting from the side of the plate-support 56. I

The pinion 53 hereinabovc referred to is fixed to the shaft 71 so thatany movement imparted to the pinion by the sliding movement of the plate5 L will impart a corresponding movement to the pinion 53, and therebyrock the switchboard 21 a suflicient distance to break the connectionthrough the switch-lever and stop the motor.

Supposing it be desired to raise the chairsupport, the switch-lever isrocked to cause the motor-shaft to rotate in a direction to raise' thesaid seat-support. As the seat-support reaches the limit of its upwardmovement it will raise the sliding plate 54:, and thus swing theswitchboard 21 into a position which will cut off the current from themotor, and thereby stop the motor.

The operator may stop the motor at any time intermediate the limits ofthe movements of the seat-support by manipulating the switch-lever.

Supposing the seat-support to be at the limit of its upward movement andit be desired to lower the same, the switch-lever is rocked in adirection tending to rotate the motor-shaft in a reverse direction. Asthe seat-support descends its abutment 68 will engage the lip 67 on thesliding plate 54 and depress the same, thus swinging the switchboard 21into a position to cut off the current and stop the motor. It will thusbe seen that the motor is automatically stopped when the seat-supportreaches the limit of its upward or downward movement, and at the sametime the operator is permitted to have full control of the motor whenthe seat-support is at the points intermediate the limits of itsmovements.

While I have shown and described my improved electric switch inconnection with a chair raising and lowering mechanism, it is to beunderstood that I do not limit myself to its use in such connection, forit is evident that the switch may be used in many different places whereit is desirable that the movement of a part should be automaticallystopped when the part reaches a predetermined point. Hence I do not wishto limit myself to the use of the switch in connection with a chairraising and lowering mechanism.

hat I claim is 1. An electric switch comprising a suitable The furthermovement of the seat support, a switch-lever and switchboard fitted toswing on the said support and spring-actuated arms engaging the leverand board and arranged to yieldingly keep the lever and board to theirnormal position with respect to each other.

2. In combination, a movable part, an electric motor for operating thesame, a switch for controlling the motor and means for operating theswitch to stop the motor when the movable part reaches a predeterminedpoint comprising a sliding plate having lips thereon near the limits ofthe sliding movement of the movable part, an abutment on the movablepart fitted to engage one or the other of the said lips as the movablepart nears the limit of its sliding movement and a connection betweenthe sliding plate and the switch whereby the movement of the plate isimparted to the switch.

3. In combination, a movable part, an electric motor for operating thesame, a switch for controlling the motor and means for operating theswitch to stop the motor comprising a sliding plate arranged to beengaged by the movable part when the part reaches a predetermined pointand a connection between the plate and switch comprising a cross-shafthaving a pinion-and-rack engagement with the switch and sliding platewhereby the movement of the plate is imparted to the switch.

4. In combination, a movable part, an electric motor for operating thesame, a switch for controlling the motor and means for operating theswitch to stop the motor comprising a sliding plate, a spring forholding the plate intermediate the limits of its sliding movement, anabutment carried by the movable part for engaging the sliding plate asthe movable part reaches a predetermined point and a connection betweenthe sliding plate and switch whereby the movement of the'plate isimparted to the switch.

5. In combination, a movable part, a motor for operating the same, aswitch for controlling the motor and. means controlled by the movablepart for operating the switch comprising a sliding plate connected tothe switch and having inwardly-turned ears, a plate-support havinggrooves in which the ears are fitted to travel and a spring in theplate-support fitted 'to engage the said ears for holding the slidingplate intermediate the limits of its sliding movement.

6. An electric switch comprising a suitable support, a switch-lever andswitchboard fitted to swing thereon, stops carried by the switchleverand switchboard and springactuated arms arranged to engage the saidstops for returning the switch-lever and switchboard to their normalposition with respect to each other when the parts are released.

7. A chair comprising a vertically-reciprocating seat-support, anelectric motor for operating the same, a switch for the motor and meansfor operating the switch to stop the motor comprising avertically-sliding plate having upper and lower lips, an abutment on theseat-support fitted to engage said lips for 5 sliding the plate and aconnection between the plate and the switch whereby the movement I ofthe plate is imparted to the switch. '8. A chair comprising avertically-reciprocating seat-support, an electric motor for op- 1crating the same, a switch for controlling the motor and means foroperating the switch to stop the motor when the seat-support reaches apredetermined point comprising a verticallysliding plate having lipsthereon, a spring for 5 holding the plate intermediate the limits of itsmovement, an abutment on the seat-support fitted to engage the said lipsfor sliding the plate and a connection between the plate and the switchwhereby the movement of the 20 plate is imparted to the switch.

9. A chair comprising a vertically-reciprocating seat-support, anelectric motor for operating the same, a switch for controlling themotor and means for operating the switch to stop the motor comprising avertically-sliding plate having lips thereon, an abutment on theseat-support fitted to engage said lips to slide the plate and across-shaft havinga pinion-and-rack engagement with the switch and thesliding plate whereby the movement of the plate is imparted to theswitch.

In testimony that I claim the foregoing as my invention I have signed myname, in presence of two witnesses, this 25th day of February, 1903.

JAMEs'F. HARDY.

Witnesses:

FREDK. HAYNES, HENRY THIEME.

